Conventional SATCOM terminals utilize mechanical means for satellite tracking, such as gimbal scan or CONSCAN with a rotating subreflector. However, for COTM (Communication On The Move) applications, random perturbations such as those due to rapid vehicle movement over tough terrain will degrade the tracking accuracy to an unacceptable level.
Prior attempts for SATCOM electronic tracking include a dual-band tracking feed, using higher order modes to form azimuth and elevation difference patterns, a dual-band feed with electronic tracking capability using a TEM coaxial mode to receive a θ varying error signal, and a monopulse implemented using a single band horn with higher order modes. In general such systems utilize large mode couplers and cannot be applied to a multi-band aperture. These systems offer pseudo-monopulse tracking only for single band or dual-band.